Phosphorous-containing calixarenes

ABSTRACT

Phosphorus-containing calixarenes of the general formula I ##STR1## and a process for their preparation are described. Additionally, a process for the preparation of aldehydes by the hydroformylation of C 3  -C 20  -olefins by means of rhodium or ruthenium carbonyl complexes, in which the phosphorus-containing calixarenes of the formula I are used as ligands, is described.

This application was filed under 35 U.S.C. 371 and was based upon PCTInternational Application No. PCT/EP94/01999, which was filed on Jun.20, 1994.

The present invention relates to phosphorus-containing calixarenes.

Carbonylation reactions are understood as meaning the production ofoxygen-containing products by reacting an organic compound with carbonmonoxide and preferably a further reactant, especially hydrogen, in thepresence of a catalyst. An industrially particularly important reactionis the hydroformylation of olefins by reaction with carbon monoxide andhydrogen with formation of aldehydes which contain one carbon atom morethan the starting materials. The catalysts used are group VIIItransition metal complexes which contain phosporus-containing ligands,for example phosphites (cf. J. Falbe, New Synthesis with CarbonMonoxide, Springer Verlag, New York 1980).

In addition to cobalt catalysts rhodium catalysts have in recent yearsbecome increasingly important for the hydroformylation of lowerα-olefins, since they permit reaction at a lower pressure. As a rule,triphenylphosphine is used in excess as the phosphorus ligand, a highligand/rhodium ratio being required in order to increase the selectivityof the reaction to give the commercially desired n-aldehyde product.

In recent years, attempts have been made to obtain more effectivephosphorus ligands for the hydroformylation. In addition to phosphiteshaving different substituents, phosphites too were tested for theirsuitability as catalysts. When these form a coordinate bond with atransition metal center, phosphites give catalysts having higheractivity, but the life of these catalyst systems is unsatisfactory owingto the considerable sensitivity of the phosphite ligands to hydrolysis.Bisaryldiol-substituted chelating polyphosphites, as described in EP-A21 46 22, are said to have dramatically reduced sensitivity tohydrolysis. The rhodium complexes of these ligands are said to formextremely active hydroformylation catalysts. EP-A 213 639 describeschelate bisphosphites which have diorganophosphite functionality at onephosphorus atom and triorganophosphite functionality at the secondphosphorus atom. EP-A 155 508 furthermore discloses the use ofbis-aryldiol-substituted monophosphites in the rhodium-catalyzedhydroformylation of sterically hindered olefins, eg. isobutene. EP-A 472071 discloses chelate bisphosphite ligands in which bis-aryldiols arelinked via bisphosphite ester bridges to alkane-diols or o-aryldiols.Finally, diol- and triol-substituted mono-phosphites and their use inhydroformylation are described in EP-A 149 894, EP-A 96 988 and EP-A 96986.

In the hydroformylation of olefins, depending on the double bondposition at which the carbon monoxide undergoes addition, straight-chainaldehydes, which are referred to as n-aldehydes, or branched aldehydes,ie. isoaldehydes, are formed. This is shown schematically in equation(1): ##STR2## However, it is generally desirable for the fraction ofn-aldehyde, referred to below as n-fraction, to be as large as possiblecompared with that of the isoaldehyde in the hydroformylation product,since the n-aldehydes lead to products having particularly advantageousplasticizer properties in the further processing of the aldehydes toplasticizer alcohols and plasticizers (cf. for example U.S. Pat. No.4,426,542).

When the chelate bisphosphite ligands of the abovementioned prior artare used, hydroformylation products having a very high n-fraction of up96% are obtained in the rhodium-catalyzed hydroformylation of olefins.

It is an object of the present invention to provide ligands for therhodium- or ruthenium-catalyzed hydroformylation of olefins, with theaid of which the n-fraction in the hydroformylation product can be evenfurther increased.

We have found that this object is achieved by phosphorus-containingcalixarenes of the general formula I ##STR3## where n is an integer from2 to 4,

R¹ is hydrogen, C₁ -C₂₀ -alkyl, C₁ -C₂₀ -alkoxy, sulfonate orcarboxylate,

the radicals R² are identical or different and are hydrogen or C₁ -C₂₀-alkyl and

X is hydrogen, C₁ -C₂₀ -alkyl, C₁ -C₂₀ -alkoxy or a phenyl or phenoxygroup which is unsubstituted or substituted by 1 to 3 C₁ -C₂₀ -alkyl, C₁-C₂₀ -alkoxy, sulfonate, carboxylate, C₁ -C₂₀ -alkylthio and/or C₂ -C₂₀-dialkylamino groups.

We have also found a process for the preparation ofphosphorus-containing calixarenes of the formula I, which comprisesreacting a calixarene of the general formula IV ##STR4## where n, R¹ andR² have the abovementioned meanings, with a phosphorus compound of thegeneral formula V

    XPHal.sub.2                                                V

where X has the abovementioned meanings and Hal is fluorine, chlorine,bromine or iodine, in the presence of a base.

We have also found a process for the preparation of aldehydes by thehydroformylation of C₂ -C₂₀ -olefins by means of a CO/H₂ gas mixture inthe presence of rhodium carbonyl complexes or ruthenium carbonylcomplexes with a phosphorus-containing ligand and in the presence of asolvent, which comprises using the phosphorus-containing calixarenes ofthe formula I as ligands.

The novel phosphorus-containing calixarenes are cyclic phosphites andphosphonites of hydroxylated calixarenes.

In the novel phosphorus-containing calixarenes of the general formula I,R¹ may be hydrogen or C₁ -C₂₀ -alkyl, preferably C₁ -C₆ -alkyl, C₁ -C₂₀-alkoxy, preferably C₁ -C₆ -alkoxy, sulfonate or carboxylate. R¹ isparticularly preferably tert-butyl, sulfonate or carboxylate.

In the novel phosphorus-containing calixarenes of the formula I, theradicals R² may be identical or different and are hydrogen or C₁ -C₂₀-alkyl, preferably C₁ -C₆ -alkyl. R² is particularly preferablyhydrogen.

In the novel phosphorus-containing calixarenes of the formula I, X maybe hydrogen, C₁ -C₂₀ -alkyl, preferably C₁ -C₆ -alkyl, C₁ -C₂₀ -alkoxy,preferably C₁ -C₆ -alkoxy, or a phenyl or phenoxy group which isunsubstituted or substituted by 1 to 3, preferably 1 or 2, C₁ -C₂₀-alkyl, preferably C₁ -C₆ -alkyl, C₁ -C₂₀ -alkoxy, preferably C₁ -C₆-alkoxy, C₁ -C₂₀ -alkylthio, preferably C₁ -C₆ -alkylthio, C₂ -C₂₀-dialkylamino, preferably C₂ -C₁₀ -dialkylamino, sulfonate orcarboxylate groups. Preferred phosphorus-containing calixarenes arethose in which X is phenoxy of the general formula II ##STR5## where R³and R⁴ may be identical or different and may each be hydrogen, C₁ -C₂₀-alkyl, preferably C₁ -C₆ -alkyl, C₁ -C₂₀ -alkoxy, preferably C₁ -C₆-alkoxy, C₁ -C₂₀ -alkylthio, preferably C₁ -C₆ -alkylthio, and/or C₂-C₂₀ -dialkylamino, preferably C₂ -C₁₀ -dialkylamino, and R⁴ mayadditionally be sulfonate or carboxylate.

The sulfonate and carboxylate groups in the novel calixarene derivativesmay be present both in protonated form, ie. as sulfo or carboxyl groups;preferred calixarenes are those in which these groups are present insalt form, for example as alkali metal, alkaline earth metal or oniumsalt, in particular as ammonium or phosphonium salt. The presence ofsulfonate or carboxylate groups in the novel phosphorus-containingcalixarenes increases their water solubility and thus facilitates thehydroformylation in an aqueous medium.

A particularly preferred phosphorus-containing calixarene is that of theformula III. ##STR6## The novel phoshorus-containing calixarenes can beobtained by reacting a hydroxyl-carrying calixarene of the generalformula IV ##STR7## where n, R¹ and R² have the abovementioned meanings,with a phosphorus compound of the general formula V

    XPHal.sub.2                                                V

where X has the abovementioned meanings and Hal is fluorine, chlorine,bromine or iodine, preferably chlorine, in the presence of a base.

Calixarenes are defined as cyclic condensates of para-substitutedphenols and aldehydes, preferably formaldehyde (cf. Chemie in unsererZeit 25 (1991), 195). They can be prepared by processes known per se, asdescribed, for example, in Gutsche, "Calixarenes", Chapter 2, pages 27to 66, The Royal Society of Chemistry, Cambridge 1989.

The phosphorus-containing compounds of the formula V which are requiredfor the preparation of the calixarene phosphites can be prepared byprocesses known per se (cf. Houben Weyl, Methoden der Org. Chemie,Volume XII/2, Chapter 2, Thieme, Stuttgart 1964), for example byreacting a phosphorus trihalide, such as phosphorus trichloride,phosphorus tribromide or phosphorus triiodide, with an alcohol or phenolin the presence of a base, such as an alkali metal or alkaline earthmetal hydroxide or carbonate or preferably a tertiary amine.

The phosphorus-containing compounds of the formula V which are requiredfor the preparation of the calixarene phosphonites can likewise beproduced by known methods (cf. Houben-Weyl, Methoden der Org. Chemie,Volume XII/1, pages 302-318, Thieme, Stuttgart 1963), for example byreacting a phosphorus trihalide, such as phosphorus trichloride, with anaromatic compound, such as benzene, in the presence of a Friedel-Craftscatalyst, such as aluminum chloride.

For the preparation of the novel calixarene derivatives, the relevantcalixarenes IV are reacted with, preferably, stoichiometric amounts ofphosphorus-containing compound V per monomer unit of the calixareneused. The formula unit as shown in the square brackets in formula IV isdefined as a monomer unit of the calixarene.

The reaction of the calixarene IV with the phosphorus compound V iscarried out in the presence of a base.

The bases used may be mineral bases, for example alkali metal oralkaline earth metal oxides, alkali metal or alkaline earth metalhydroxides or alkali metal or alkaline earth metal carbonates, but thereaction is preferably carried out in the presence of tertiary amines,preferably tertiary aliphatic amines of 3 to 30 carbon atoms, forexample trimethylamine, triethylamine, tri-n-propylamine,ethyldiisopropylamine, triisopropylamine, tributylamine, etc. The baseis added in a molar ratio of from 1 to 200, preferably from 1.5 to 100,particularly preferably from 2 to 10, based on the amount of thephosphorus compound V used.

The preparation of the novel calixarene derivatives is advantageouslycarried out in a solvent. The solvent used may be any solvent which isinert under the reaction conditions, preferably aromatic hydrocarbons,such as benzene, toluene or xylene, or ethers such as diethyl ether,diisopropyl ether, methyl tert-butyl ether, tetrahydrofuran, dioxane,ethylene glycol dimethyl ether, etc.

The reaction is carried out in general at from -40°0 to 100° C. Thepressure used is in general not critical for the reaction, butatmospheric pressure or the autogenous pressure of the reaction systemis advantageously employed.

The novel phosphorus-containing calixarenes serve as ligands for rhodiumand ruthenium in the rhodium- or ruthenium-catalyzed hydroformylation ofC₃ -C₂₀ -olefins. The olefins used may be olefins having internal doublebonds, α-olefins preferably being hydroformylated by the presentprocess.

The rhodium and the ruthenium are introduced into the novel process in aconventional manner in the form of salts, for example as rhodium orruthenium acetate or acetonylacetonate, as rhodium oxide or rutheniumoxide or as rhodium or ruthenium carbonyls. The type of compound inwhich the rhodium or ruthenium is used in the novel process is ingeneral not critical since, under the hydroformylation conditions usedand in the presence of the CO/H₂ reaction gas, these compounds are allconverted into the catalytically active rhodium or ruthenium specieswhich are homogeneously dissolved in the hydroformylation medium and arethen complexed and stabilized by the phosphorus-containing calixarenes.The chemical nature of these catalytically active rhodium and rutheniumspecies could not be definitively determined, although there are anumber of ideas among those skilled in the art with regard to theirchemical structure, although it has not been possible finally to proveall of them.

Since the catalytically active rhodium or ruthenium compounds aregenuine catalysts, ie. remain virtually completely unconsumed in thereaction and as such have high activity, very small amounts of rhodiumor ruthenium compounds are sufficient for catalyzing thehydroformylation with satisfactory conversion. In general, the molarratio of rhodium or ruthenium to the olefin used is from 1:1000 to1:50,000, preferably from 1:1000 to 1:5000, in the steady-statereaction.

In the case of the novel phosphorus-containing calixarenes used, themolar ratio of calixarene to rhodium or ruthenium is in general from 1:1to 100:1, preferably from 1:1 to 20:1, particularly preferably from 1:1to 5:1.

The CO/H₂ molar ratio of the CO/H₂ mixture fed to the hydroformylationmay be from 20:1 to 1:20, preferably from 1:1 to 20:1, particularlypreferably 1:1.

The novel hydroformylation process is generally carried out in thepresence of a solvent. The solvent used may be virtually any solventwhich is inert under the hydroformylation conditions, for examplehydrocarbons, esters or alcohols, but the aldehydes which are formed inthe hydroformylation of the relevant olefin are preferably used assolvents in the hydroformylation. Other particularly preferred solventsare high boilers, ie. mixtures of high-boiling compounds, such as thoseformed during the hydroformylation reaction as byproducts in a number ofsecondary reactions, such as aldol condensations, eliminations,disproportionations and hydrogenations, from the aldehydes formed duringthe hydroformylation. A number of such high boilers and the method oftheir formation are described by way of example in U.S. Pat. No.4,148,830 for the preparation of butyraldehyde.

The novel process is carried out in general at from 30° to 150° C.,preferably from 60°0 to 130° C., particularly preferably from 90° to110° C., and at in general from 1×10³ to 1×10⁷, preferably from 1×10⁵ to5×10⁶, particularly preferably from 5×10⁵ to 3×10⁶, Pa.

The novel hydroformylation process can be carried out batchwise but ispreferably operated continuously. Conventional process engineering, asdescribed, for example, in U.S. Pat. No. 4,148,830, U.S. Pat. No.4,329,511 or EP-A 313 559, may be used.

With the novel phosphorus-containing calixarenes as ligands for thecatalytically active rhodium or ruthenium compounds, the n-fraction inthe hydroformylation product can surprisingly be increased to 99.5% inthe novel hydroformylation process.

EXAMPLES Preparation of Phosphorus-Containing Calixarene III ##STR8##23.6 g (0.1 mol) of 3,5-di-tert-butyl-4-hydroxyanisole (commerciallyavailable or preparable according to J. Am. Chem. Soc. 77 (1955), 1672)were dissolved in 500 ml of toluene, and 50 ml of toluene were distilledoff from this mixture. 68.2 ml (0.5 mol) of triethylamine were added tothe cooled solution at room temperature, and the mixture was thenmetered into a solution, pre-cooled to -40° C., of 8.8 ml (0.1 mol) ofphosphorus trichloride in 1 l of toluene. The solution was slowly warmedup to room temperature, stirred for 1 hour at room temperature and thenheated at 100° C. for a further 10 hours. The resulting solution of thecompound VI was fed in this form to stage 2. ##STR9##

32.4 g (0.05 mol) of calix-4-arene VII (obtainable according to Gutsche"Calixarenes", Chapter 2, pages 27-66) were added in powder form to thesolution of compound VI from the 1st stage, and this mixture was cooledto -40° C. A solution of 136.5 ml (1 mol) of triethylamine in 500 ml oftoluene was metered into this mixture. The reaction mixture was slowlywarmed up to room temperature and stirred for 1 hour at room temperatureand for a further 10 hours at 100° C. The precipitated triethylammoniumchloride was then filtered off from the reaction solution and washedwith toluene. The toluene was removed from the combined toluene extractsby distillation, a light brown, viscous residue remaining. This waswashed with pentane and then extracted with 400 ml of acetonitrile underreflux. After a part of the residue had dissolved, the remaining powderwas filtered off, washed with pentane and dried.

The ¹ H- and ¹³ C-NMR spectra confirmed the structure according toformula III. In the ³¹ P-NMR spectra, a signal was observed at 121 ppm,based on phosphoric acid as standard.

Elemental analysis result (theory)!: C 75.5% (76.2%); H 8.3% (8.9%); O10.9% (9.9%); P 5.3% (5.1%).

The mass spectrum of III had a molecular peak at 1176 Dalton as the maincomponent.

Example 2 Hydroformylation of 1-octene

In a 0.35 l autoclave, a mixture of 56.9 g of 1-octene (508 mmol), 0.032g (0.124 mmol) of rhodium in the form of the complex Rh(CO)₂ (acac)(acac=acetylacetonate) and 0.7098 g (0.604 mmol) of the compound III in70 ml of Texanol® (2,2,4-trimethylpentane-1,3-diol monoisobutyrate) isheated to 100° C., and a pressure of 2×10⁶ Pa was established by passinga CO/H₂ mixture (CO/H₂ volume ratio=1:1) into the autoclave and was keptconstant during the total duration of the reaction by furtherintroduction of this gas mixture. After a reaction time of 8 hours, thehydroformylation mixture was analyzed by gas chromatography. The resultof this analysis is shown in the table.

                  TABLE                                                           ______________________________________                                        int. C.sub.8 -olefins                                                                         3.41% by weight                                                                             0.0386 mol                                      1-Octene       16.58"         0.1879 mol                                      Octane          7.84"         0.0873 mol                                      2-Propylhexanal                                                                               0.00"                                                         2-Ethylheptanal                                                                               0.00"                                                         2-Methyloctanal                                                                               0.11"         0.0010 mol                                      n-Nonanal      21.84"         0.1952 mol                                      Texanol        45.8"                                                          Others          0.0"                                                          Total          95.6"                                                          Conversion                   63 mol %                                         Yield of nonanal             39 mol %                                         Yield of octane              17 mol %                                         Selectivity (based on 1-octene converted)                                     Nonanals       61%                                                            Octane         27%                                                            internal olefins                                                                             12%                                                            ______________________________________                                         The molar ratio of 1nonanal to the total amount of nonanals was 99.5:0.5.

By increasing the reaction time, the conversion can be further increasedwithout any decrease in the n-aldehyde selectivity of the catalyst.

We claim:
 1. A phosphorus-containing calixarene of the formula I##STR10## where n is an integer from 2 to 4,R¹ is hydrogen, C₁ -C₂₀-alkyl, C₁ -C₂₀ -alkoxy, sulfonate or carboxylate, the radicals R² areidentical or different and are hydrogen or C₁ -C₂₀ -alkyl and X ishydrogen, C₁ -C₂₀ -alkyl, C₁ -C₂₀ -alkoxy or a phenyl or phenoxy groupwhich is unsubstituted or substituted by 1 to 3 C₁ -C₂₀ -alkyl, C₁ -C₂₀-alkoxy, sulfonate, carboxylate, C₁ -C₂₀ -alkylthio or C₂ -C₂₀-dialkylamino groups.
 2. A phosphorus-containing calixarene as claimedin claim 1, in which X is phenyloxy of the formula II ##STR11## where R³and R⁴ are identical or different and are each hydrogen, C₁ -C₂₀ -alkyl,C₁ -C₂₀ -alkoxy, C₁ -C₂₀ -alkylthio or C₂ -C₂₀ -dialkylamino and R⁴ mayadditionally be sulfonate or carboxylate.
 3. A phosphorus-containingcalixarene as claimed in claim 2, in which R¹ is hydrogen, C₁ -C₆-alkyl, C₁ -C₆ -alkoxy, sulfonate or carboxylate, and R² is hydrogen. 4.A phosphorus-containing calixarene as claimed in claim 1, of the formulaIII ##STR12##
 5. A process for the preparation of aphosphorus-containing calixarene as claimed in claim 1, which comprisesreacting a calixarene of the formula IV ##STR13## where n, R¹ and R²have the meanings stated in claim 1, with a phosphorus compound of theformula V

    XPHal.sub.2                                                V

where X has the meanings stated in claim 1 and Hal is fluorine,chlorine, bromine or iodine, in the presence of a base.
 6. A process asclaimed in claim 5, wherein the base used is a C₃ -C₃₀ -trialkylamine.7. In a process for the preparation of an aldehyde by thehydroformylation of a C₁₀ -C₂₀ -olefin by means of a CO/H₂ gas mixturein the presence of a rhodium or ruthenium carbonyl complex with aphosphorus-containing ligand and in the presence of a solvent, theimprovement which comprises carrying out the hydroformylation reactionin the presence of at least one phosphorous-containing calixarene asclaimed in claim
 1. 8. A process as claimed in claim 7, wherein thehydroformylation is carried out at from 30° to 150° C. and from 1×10³ to1×10⁷ Pa.
 9. A process as claimed in claim 7, wherein the solvent usedis the aldehyde which is formed by the hydroformylation of theparticular olefin reactant.
 10. A process as claimed in claim 7, whereinthe solvent used is a mixture of high-boiling compounds which arebyproducts formed during the hydroformylation of an olefin reactant bysecondary reactions of the resulting aldehyde product.
 11. A process asclaimed in claim 7, wherein an α-olefin is hydroformylated.